1. Field of the Invention
This invention relates to a jetted bathtub having a jet nozzle for ejecting a jet flow into a bathtub, and more particularly to a jetted bathtub in which a jet flow swirling about the nozzle central axis is ejected.
2. Background Art
It is conventionally known that a jet flow is ejected into a bathtub from a jet nozzle disposed on a wall. In most of such techniques, the jet flow is ejected straight and locally hits a portion of the bather's body. Thus, the stimulus provided by the jet flow is monotonous and boring, and it is difficult to achieve diversity in massage feeling.
JP-A 2001-8998(Kokai) discloses a nozzle apparatus comprising a nozzle body having a generally circular outer shape and rotatably housed in a unit jet port cover, and an orifice for squirting water in a bathtub into the jet hole of the nozzle body at a prescribed pressure. The jet port of the jet hole disposed inside the nozzle body is decentered from the shaft position. The water in the bathtub is squirted through the orifice into the jet hole of the nozzle body at a prescribed pressure and mixed with air to form a bubble-mixed jet flow, which is squirted from the jet port of the jet hole into the bathtub. At this time, the nozzle body is rotated by the jet flow from the orifice, because the jet port of the nozzle body is disposed at a position decentered with respect to the shaft position. This results in a rotary jet flow with changing squirt direction of the jet flow.
However, in JP-A 2001-8998(Kokai), the configuration for rotating the nozzle body to produce a rotary jet flow complicates the structure for rotatably supporting the nozzle body, thus interfering with cost-effective fabrication. Furthermore, there is concern about the decrease of rotation performance due to wear and clogging in the rotary sliding portion.
Moreover, the configuration disclosed in JP-A 2001-8998(Kokai) has a doubly nested structure in which a cylindrical nozzle body is rotatably provided in a cylindrical attachment member attached to the wall. This complicates the structure, and includes a narrow gap between the nozzle body corresponding to an inner tube and the attachment member corresponding to an outer tube. Thus, there is also concern about clogging of the gap with dust.
An apparatus disclosed in JP-A 2-128765(Kokai) includes a narrow gap between a structure (corresponding to an inner tube), the inner surface of which serves as a guiding wall having a channel width gradually expanding toward the downstream side, and the inner wall surface of a structure (corresponding to an outer tube) attached to a wall. The gap serves as a channel for allowing part of the water flowing downstream to flow back to the upstream side. Thus, the apparatus disclosed in JP-A 2-128765(Kokai) also has a double structure. Hence the structure is complicated, and there is concern about clogging of the narrow channel (gap).
A nozzle disclosed in JP-A 4-61859(Kokai) also has a double structure. Likewise, the structure is complicated, and there is concern about clogging of the narrow channel (gap).
In an apparatus disclosed in JP-A 4-1764-61(Kokai), the jet flow undergoes reciprocating motion. Hence the stimulus to the bather's body follows a linear trajectory, which is insufficient to serve as a stimulated area. Furthermore, the jet nozzle disclosed in JP-A 4-176461(Kokai) is intended to eject water into the air, and cannot provide stimuli to some portions of the bather's body located in water in the normal bathing posture such as the hip, back, flanks, arms, calves, and soles.